Ischemia-induced activation of AMPK does not increase glucose uptake in glycogen-replete isolated working rat hearts.

Alterations in myocardial glucose metabolism are a key determinant of ischemia-induced depression of left ventricular mechanical function. Since myocardial glycogen is an important source of endogenous glucose, we compared the effects of ischemia on glucose uptake and utilization in isolated working rat hearts in which glycogen content was either replete (G replete, 114 micromol/g dry wt) or partially depleted (G depleted, 71 mumol/g dry wt). The effects of low-flow ischemia (LFI, 0.

Sensory profiles of bread made from paired samples of organic and conventionally grown wheat grain.

The Canadian hard red spring wheat cultivar "Park" was grown in 2005 in Edmonton, AB, Canada on both conventionally and organically managed land, situated less than 1 km apart. Grains from the paired wheat samples were compared for cereal-grain-quality attributes. For sensory analysis, organically and conventionally produced wheat grains were milled into flour and baked into 60% whole wheat bread.

Impaired pulmonary oxygen uptake kinetics and reduced peak aerobic power during small muscle mass exercise in heart transplant recipients.

We examined peak and reserve cardiovascular function and skeletal muscle oxygenation during unilateral knee extension (ULKE) exercise in five heart transplant recipients (HTR, mean +/- SE; age: 53 +/- 3 years; years posttransplant: 6 +/- 4) and five age- and body mass-matched healthy controls (CON). Pulmonary oxygen uptake (Vo(2)(p)), heart rate (HR), stroke volume (SV), cardiac output (Q), and skeletal muscle deoxygenation (HHb) kinetics were assessed during moderate-intensity ULKE exercise. Peak exercise and reserve Vo(2)(p), Q, and systemic arterial-venous oxygen difference (a-vO(2diff)) were 23-52% lower (P < 0.

Suppressing the excitability of spinal motoneurons by extracellularly applied electrical fields: insights from computer simulations.

The effect of extracellularly applied electrical fields on neuronal excitability and firing behavior is attributed to the interaction between neuronal morphology and the spatial distribution and level of differential polarization induced by the applied field in different elements of the neuron. The presence of voltage-gated ion channels that mediate persistent inward currents (PICs) on the dendrites of spinal motoneurons enhances the influence of electrical fields on the motoneuronal firing behavior. The goal of the present study was to investigate, with a realistic motoneuron computer model, the effects of extracellularly applied electrical fields on the excitability of spinal motoneurons with the aim of reducing the increased motoneuronal excitability after spinal cord injury (SCI).

Neuropeptide FF and neuropeptide VF inhibit GABAergic neurotransmission in parvocellular neurons of the rat hypothalamic paraventricular nucleus.

Neuropeptide FF (NPFF) and neuropeptide VF (NPVF) are octapeptides belonging to the RFamide family of peptides that have been implicated in a wide variety of physiological functions in the brain, including central autonomic and neuroendocrine regulation. The effects of these peptides are mediated via NPFF1 and NPFF2 receptors that are abundantly expressed in the rat brain, including the hypothalamic paraventricular nucleus (PVN), an autonomic nucleus critical for the secretion of neurohormones and the regulation of sympathetic outflow. In this study, we examined, using whole cell patch-clamp recordings in the brain slice, the effects of NPFF and NPVF on inhibitory GABAergic synaptic input to parvocellular PVN neurons.

Adequate oral threonine is critical for mucin production and gut function in neonatal piglets.

In previous experiments, we found that the threonine requirement of neonatal piglets fed parenterally was 40% of that when fed intragastrically; we hypothesized that much of the oral supply of threonine is being used for mucin production. To investigate this hypothesis, intragastrically fed 2-day-old piglets were fed one of three treatments for 8 days: 1) a threonine-adequate diet (IG-A; 0.6 g threonine.

V-H+ -ATPase translocation during blood alkalosis in dogfish gills: interaction with carbonic anhydrase and involvement in the postfeeding alkaline tide.

We investigated the involvement of carbonic anhydrase (CA) in mediating V-H(+)-ATPase translocation into the basolateral membrane in gills of alkalotic Squalus acanthias. Immunolabeling revealed that CA is localized in the same cells as V-H(+)-ATPase. Blood plasma from dogfish injected with acetazolamide [30 mg/kg at time (t) = 0 and 6 h] and infused with NaHCO(3) for 12 h (1,000 microeq.

Expression of an active LKB1 complex in cardiac myocytes results in decreased protein synthesis associated with phenylephrine-induced hypertrophy.

AMP-activated protein kinase (AMPK) is a major metabolic regulator in the cardiac myocyte. Recently, LKB1 was identified as a kinase that regulates AMPK. Using immunoblot analysis, we confirmed high expression of LKB1 in isolated rat cardiac myocytes but show that, under basal conditions, LKB1 is primarily localized to the nucleus, where it is inactive.

Cardiac hypertrophy in anion exchanger 1-null mutant mice with severe hemolytic anemia.

Anion exchanger 1 (AE1; SLC4A1), the plasma membrane Cl(-)/HCO(3)(-) exchanger of erythrocytes, is also expressed in heart. The aim of this study was to assess the role of AE1 in heart function through study of AE1-null (AE1(-/-)) mice, which manifest severe hemolytic anemia resulting from erythrocyte fragility. Heart weight-to-body weight ratios were significantly higher in the AE1(-/-) mice than in wild-type (AE1(+/+)) littermates at both 1-3 days postnatal (3.

Interactions between Na+ channels and Na+-HCO3- cotransporters in the freshwater fish gill MR cell: a model for transepithelial Na+ uptake.

Isolated mitochondria-rich (MR) cells from the rainbow trout gill epithelium were subjected to intracellular pH (pH(i)) imaging with the pH-sensitive dye BCECF-AM. MR cells were categorized into two distinct functional subtypes based on their ability to recover pH(i) from an NH(4)Cl-induced acidification in the absence of Na(+). An apparent link between resting pH(i) and Na(+)-independent pH(i) recovery was made.

Effects of adenosine on myocardial glucose and palmitate metabolism after transient ischemia: role of 5'-AMP-activated protein kinase.

Loss of cardioprotection by adenosine in hearts stressed by transient ischemia may be due to its effects on glucose metabolism. In the absence of transient ischemia, adenosine inhibits glycolysis, whereas it accelerates glycolysis after transient ischemia. Inasmuch as 5'-AMP-activated protein kinase (AMPK) is implicated as a regulator of glucose and fatty acid utilization, this study determined whether a differential alteration of AMPK activity contributes to acceleration of glycolysis by adenosine in hearts stressed by transient ischemia.

Adenosine stimulates depolarization and rise in cytoplasmic [Ca2+] in type I cells of rat carotid bodies.

During hypoxia, the level of adenosine in the carotid bodies increases as a result of ATP catabolism and adenosine efflux via adenosine transporters. Using Ca2+ imaging, we found that adenosine, acting via A2A receptors, triggered a rise in cytoplasmic [Ca2+] ([Ca2+]i) in type I (glomus) cells of rat carotid bodies. The adenosine response could be mimicked by forskolin (but not its inactive analog), and could be abolished by the PKA inhibitor H89.

Cloning of rainbow trout SLC26A1: involvement in renal sulfate secretion.

The kidney plays an important role in ion regulation in both freshwater and seawater fish. However, ion transport mechanisms in the teleost kidney are poorly understood, especially at the molecular level. We have cloned a kidney-specific SLC26 sulfate/anion exchanger from rainbow trout (Oncorhynchus mykiss) that is homologous to the mammalian SLC26A1 (Sat-1).

Proinflammatory cytokines inhibit human placental 11beta-hydroxysteroid dehydrogenase type 2 activity through Ca2+ and cAMP pathways.

Excessive fetal exposure to glucocorticoids has been implicated in the etiology of adult metabolic and cardiovascular disease. Placental 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) may protect the fetus from excessive glucocorticoid exposure. Maternal stress may be accompanied by elevated levels of cortisol and increased proinflammatory cytokines [interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha (TNF-alpha)].

Chronic activation of PPARalpha is detrimental to cardiac recovery after ischemia.

High fatty acid oxidation (FAO) rates contribute to ischemia-reperfusion injury of the myocardium. Because peroxisome proliferator-activated receptor (PPAR)alpha regulates transcription of several FAO enzymes in the heart, we examined the response of mice with cardiac-restricted overexpression of PPARalpha (MHC-PPARalpha) or whole body PPARalpha deletion including the heart (PPARalpha-/-) to myocardial ischemia-reperfusion injury. Isolated working hearts from MHC-PPARalpha and nontransgenic (NTG) littermates were subjected to no-flow global ischemia followed by reperfusion.

Increased myogenic tone in 7-month-old adult male but not female offspring from rat dams exposed to hypoxia during pregnancy.

Intrauterine growth restriction (IUGR) increases the risk of cardiovascular disease later in life. Vascular dysfunction occurs in adult offspring from animal models of IUGR including maternal undernutrition, but the influence of reduced fetal oxygen supply on adult vascular function is unclear. Myogenic responses, essential for vascular tone regulation, have not been evaluated in these offspring.

Randomized controlled trial of exercise and blood immune function in postmenopausal breast cancer survivors.

The objective was to determine the effects of exercise training on changes in blood immune function in postmenopausal breast cancer survivors. Fifty-three postmenopausal breast cancer survivors were randomly assigned to an exercise (n=25) or control group (n=28). The exercise group trained on cycle ergometers three times per week for 15 wk.

Arginine synthesis does not occur during first-pass hepatic metabolism in the neonatal piglet.

We have shown that first-pass intestinal metabolism is necessary for approximately 50% of whole body arginine synthesis from its major precursor proline in neonatal piglets. Furthermore, the intestine is not the site of increased arginine synthesis observed during dietary arginine deficiency. Primed constant intravenous (iv) and intraportal (ip) infusions of L-[U-14C]proline, and iv infusion of either L-[guanido-14C]arginine or L-[4,5-3H]arginine were used to measure first-pass hepatic arginine synthesis in piglets enterally fed either deficient (0.

Noradrenergic modulation of XII motoneuron inspiratory activity does not involve alpha2-receptor inhibition of the Ih current or presynaptic glutamate release.

Norepinephrine has powerful and diverse modulatory effects on hypoglossal (XII) motoneuron activity, which is important in maintaining airway patency. The objective was to test two hypotheses that alpha2-adrenoceptor-mediated, presynaptic inhibition of glutamatergic inspiratory drive (Selvaratnam SR, Parkis MA, and Funk GD. Brain Res 805: 104-115, 1998) and postsynaptic inhibition of the hyperpolarization-activated inward current (Ih) (Parkis MA and Berger AJ.

Adrenomedullin in the rostral ventrolateral medulla increases arterial pressure and heart rate: roles of glutamate and nitric oxide.

This study was done to investigate the effects of microinjections of adrenomedullin (ADM), a vasoactive neuropeptide, in the rostral ventrolateral medulla (RVLM) on mean arterial pressure (MAP) and heart rate (HR) in urethane-anesthetized rats, and to assess the potential roles of glutamate and nitric oxide (NO) in these effects. Unilateral injections of ADM (0.01 or 0.

Reductions in the incidence of nitrofen-induced diaphragmatic hernia by vitamin A and retinoic acid.

Congenital diaphragmatic hernia (CDH) is a serious medical condition in which the developing diaphragm forms incompletely, leaving a hole through which the abdominal contents can enter the thoracic space and interfere with lung growth. A perturbation of the retinoid system has been linked to the etiology of CDH. This includes findings that nitrofen, which induces CDH in rodents, inhibits the key enzyme for retinoic acid (RA) production, retinaldehyde dehydrogenase-2 (RALDH2) in vitro.

A vibrator prevents streaming during close-arterial infusion into the kidney.

Close-arterial infusion of test substances allows one to study the responses of a selected vascular bed without inducing confounding systemic effects. Unfortunately, laminar flow patterns within the artery cause streaming of the injected factor, so that distribution within the target organ is not homogeneous. We describe a reliable method of overcoming these problems.

Activation of AMP-activated protein kinase reduces cAMP-mediated epithelial chloride secretion.

AMP-activated protein kinase (AMPK) is activated in response to fluctuations in cellular energy status caused by oxidative stress. One of its targets is the cystic fibrosis transmembrane conductance regulator (CFTR), which is the predominant Cl- secretory channel in colonic tissue. The aim of this study was to determine the role of AMPK in the modulation of colonic chloride secretion under conditions of oxidative stress and chronic inflammation.

Late potentials in female triathletes before and after prolonged strenuous exercise.

The objectives of this study were to evaluate the prevalence of late potentials (LP) in female triathletes before and after prolonged strenuous exercise (PSE), and to determine whether LP are related to greater left ventricular (LV) dimensions and/or mass. Thirteen female triathletes were examined immediately before (Pre), one hour after (Post), and 24 to 48 hours after PSE (Recovery) using signal-averaged electrocardiography (SAECG). Late potentials were evaluated by two or more standard SAECG anomalies.

Responses of red-osier dogwood to oil sands tailings treated with gypsum or alum.

The application of composite or consolidated tailings (CT) technology provides Alberta's oil sands industry with a means of reducing the volume of the fines fraction in extraction tailings and allows for faster reclamation and revegetation of mining sites. This study examined the effects of coagulant aids (gypsum and alum), used in the production of CT, on the ion content, growth, and survival of greenhouse-grown red-osier dogwood (Cornus sericea L. subsp.